1. Field of the Invention
The present invention relates to a semiconductor device and a manufacturing method thereof, and in particular, relates to a semiconductor device in which a cavity (a hole, an opening, a pore, and the like) is prevented from being produced at a crystalline semiconductor film and a manufacturing method thereof.
2. Description of the Related Art
When an amorphous silicon film is added with a metal such as Ni and heat treatment is applied thereto, a crystalline silicon film can be formed at low temperature in short time. Subsequently, a natural oxide film that is formed incidentally on the crystalline silicon film due to the heat treatment is removed by using diluted hydrofluoric acid. As the crystalline silicon film at this stage has many crystal defects, electromagnetic energy is supplied to the crystalline silicon film in the subsequent step. Consequently, a high-quality crystalline silicon film with few crystal defects can be obtained. Laser light such as excimer laser light typifies the electromagnetic energy as a specific example. A crystalline silicon film manufactured by this method can be used for manufacturing an electronic device such as a high-performance thin film transistor (TFT).